1. Field of Invention
This invention relates to substituted polybenzimidazole products and a process for their production. More particularly, this invention relates to cynoethyl derivatives of hydroxyethylated polybenzimidazole polymers and a process for their production.
2. Prior Art
Polybenzimidazoles are a known class of heterocylic polymers which are characterized by a high degree of thermal and chemical stability. Processes for their production are disclosed in U.S. Pat. No. Re. 26,065, and U.S. Pat. Nos. 3,313,783, 3,509,108, 3,555,389, 3,433,772, 3,408,336, 3,549,603, 3,708,439, 4,154,919 and 4,312,976 (all patents are herein incorporated by reference). Polybenzimidazole polymers have been formed into membranes, ultrafilters, reverse osmosis devices and other types of separatory media of great utility.
While polybenzimidazole polymers are generally chemically resistant, reaction at the imidazole nitrogen-hydrogen bond will occur under certain conditions. One method of limiting the reactivity of polybenzimidazole polymers is to chemically modify the polymer. For example, U.S. Pat. Nos. 4,020,142 and 4,154,919, disclose polyenzimidazole polymers which have been crosslinked to remove the reactive nitrogen-hydrogen bond on the imidazole ring.
In another effort to reduce the chemical reactivity of polybenzimidazole polymers, the hydrogen bonded to the the imidazole nitrogen has been replaced by various less reactant substituents. For example, U.S. Pat. No. 3,578,644 discloses an hydroxyl substitution onto the polybenzimidazole polymer by the reaction of an omega-halo-alkanol or 1,2-alkylene oxide with the polybenzimidazole polymer. See also, U.S. Pat. No. 4,599,388 which discloses a different process for the production of hydroxyl substituted polybenzimidazole polymers. However, neither of these patents disclose substituted hydroxyethylated polybenzimidazole polymers, in general, or cyanoethyl-substituted hydroxyethylated polybenzimidazole polymers, in particular.
U.S. Pat. No. 3,943,125 discloses various substituted polybenzimidazole polymers produced by the reaction of substituted tetramino pyridines or their acid salts with a suitable acid halide or dianhydride. While the patent broadly discloses a large number of substituted tetramino compounds, it fails to disclose the process for their preparation. It also specifically fails to disclose cyanoethyl-substituted hydroxyethylated polybenzimidazole polymers or a process for its production.
In addition, other substituted polybenzimidazole polymers are disclosed in U.S. Pat. Nos. 3,518,234 and 4,377,546. However, neither patent discloses cyanoethyl-substituted hydroxyethylated polybenzimidazole polymers.
It is therefore an object of this invention to produce novel substituted hydroxyethylated polybenzimidazole polymers.
It is another object of this invention to produce substituted hydroxyethylated polybenzimidazole polymers which exhibit a high degree of resistance to chemical attack and which are stable at high temperatures.
It is an additional object of this invention to produce a cyanoethyl hydroxyethylated polybenzimidazole polymer using an hydroxyethylated polybenzimidazole polymer as the precursor polymer.
It is a further object of this invention to produce cyanoethyl hydroxyethylated polybenzimidazole polymers wherein the cyanoethylation substitution is substantially complete.
These and other objects as well as the scope, nature, and utilization of this invention will be apparent to those skilled in the art from the following detailed description and appended claims.